Product Overview
The Resilient Seated Non-Rising Stem Gate Valve delivers bi-directional, zero-leakage fluid isolation for water networks, municipal wastewater, fire protection, and industrial utilities. Engineered with an EPDM/NBR encapsulated wedge and a smooth ductile iron body, this resilient seated non-rising stem gate valve ensures a tight seal with minimal pressure drop. Its non-rising stem design saves vertical headroom, making it the ideal resilient seated gate valve for buried pipelines, shallow vaults, and space-limited pump stations.
Technical Specifications
|
Parameter |
Standard Specification |
Options |
|
Size Range |
DN40 to DN600 (1.5" to 24") |
Larger sizes on request |
|
Pressure Rating |
PN10 / PN16 / Class 150 |
PN25 |
|
Design Standards |
BS EN 1074, DIN 3352, AWWA C509/C515 |
ISO standards |
|
Body / Bonnet |
Ductile Iron EN-GJS-450-10 |
- |
|
Wedge Material |
Ductile Iron core + EPDM or NBR rubber |
Vulcanized coating |
|
Stem Material |
Stainless Steel 420 / 304 / 316 |
High-tensile alloy |
|
Coating |
Fusion Bonded Epoxy (FBE) >= 250 µm |
WRAS / NSF certified |
|
Connections |
Flanged per EN 1092-2, ANSI B16.1/B16.5 |
Raised face / Flat face |
|
Drive Options |
Handwheel, Square Cap, Gearbox, Actuator |
Electric / Pneumatic |
|
Temperature |
EPDM: -10°C to +120°C / NBR: -10°C to +80°C |
Based on elastomer |
Key Features of Resilient Seated Non-Rising Stem Gate Valve
Compact Vertical Footprint
The stem rotates within a fixed height, making subterranean and vault installations simple without requiring overhead clearance.
Zero-Leakage Rubber Wedge
High-ductility iron core vulcanized with EPDM or NBR rubber creates a tight seal even in pipelines carrying light suspended solids.
Unobstructed Full Passage
Lifts the gate entirely out of the flow path when opened, reducing friction loss and allowing inline cleaning tools to pass through.
Durable Epoxy Shield
Electrostatic fusion-bonded epoxy protects interior and exterior surfaces against soil moisture, chemical exposure, and corrosion.
Pressure-Replaceable Seals
Multiple O-ring stem seals allow routine seal maintenance under working pipeline pressure, preventing unscheduled downtime.
Low Operating Torque
Self-lubricating copper alloy stem nuts and anti-friction washers ensure smooth handwheel operation over thousands of cycles.
How the Valve Works
The valve translates rotational torque from the operating wheel into linear gate travel using internal stem threading:
To Open: Turning the stem counter-clockwise pulls the rubber-coated wedge upward into the bonnet, opening the full pipeline bore for unobstructed flow.
To Close: Turning clockwise drives the wedge downward. The elastomeric surface compresses against the inner body wall to seal off flow securely.
Typical Construction and Materials
|
Operating Mechanism |
Handwheel, Square Cap, or Gearbox |
|
Stem |
Stainless Steel (304 / 316 / 420) |
|
Bonnet |
Ductile Iron EN-GJS-450 |
|
Stem Nut |
Low-Friction Copper Alloy |
|
Sealing Wedge |
Ductile Iron encapsulated in EPDM or NBR |
|
Body |
Ductile Iron with Fusion Bonded Epoxy Coating |
Key Applications of Resilient Seated Non-Rising Stem Gate Valve
Potable Water Distribution
Provides clean isolation in municipal networks, treatment facilities, and distribution lines using safe, certified coatings.
Shallow Underground Vaults
Fits easily into subterranean chambers and trenches where vertical clearance prohibits rising stem valves.
Wastewater Management
Resists raw sewage, mud, and organic sediment buildup through the sealing action of the resilient wedge face.
Fire Mains and Protection
Delivers reliable standby isolation for industrial fire suppression lines, ring networks, and high-pressure pumps.
Industrial Utility Loops
Manages cooling loops, raw water lines, and HVAC water circuits across industrial manufacturing plants.
Comparison: Non-Rising Stem (NRS) vs. Rising Stem (OS&Y)
|
Feature |
Non-Rising Stem (NRS) |
Rising Stem (OS&Y) |
|
Stem Movement |
Internal rotation only |
Moves vertically out of bonnet |
|
Space Needed |
Low height footprint |
High vertical clearance required |
|
Position Check |
Mechanical indicator optional |
Visual stem height shows state |
|
Thread Protection |
Enclosed inside valve body |
Exposed to dirt and weather |
|
Primary Placement |
Buried pipelines, valve pits |
Above-ground plants, pump rooms |
Packaging and Export Standards
To protect machined flanges and epoxy coatings during ocean transport, each shipment follows precise export handling:
Flange Protection: End covers shield sealing faces from impact and grit.
Surface Wrap: Protective wrapping preserves the fusion-bonded epoxy surface.
Export Crating: Heat-treated ISPM 15 wooden cases or secured pallets ensure structural integrity during sea freight.
Clear Identification: Outer markings display valve size, pressure, heat numbers, and handling details for easy site receiving.
FAQ
Q: Why choose a resilient seated gate valve over a traditional metal seated valve?
A: Resilient seated valves use a flexible rubber-coated wedge that forms a bubble-tight seal against smooth body walls. They eliminate the bottom seating recess where grit accumulates, preventing seal damage in dirtier water services.
Q: Can this valve be installed horizontally or vertically?
A: Yes. It works effectively in horizontal and vertical runs. For larger sizes (DN350 and above) mounted horizontally, adding a gearbox or internal wedge guides helps maintain alignment and easy operation.
Q: How do I select between EPDM and NBR wedge rubber?
A: Select EPDM for drinking water, HVAC circuits, and general utility lines. Choose NBR if the medium contains trace hydrocarbons, oils, or industrial wastewater chemicals.
Q: Can this valve be used for continuous flow regulation?
A: No. Gate valves are designed purely for isolation (fully open or fully closed). Throttling in a partially open state causes fluid velocity to vibrate and wear down the elastomeric wedge.
Q: Is the internal coating safe for drinking water?
A: Yes. The standard non-toxic, electrostatic fusion-bonded epoxy powder coating (minimum 250 microns) complies with major global drinking water safety requirements.
Q: Can stem O-rings be replaced under line pressure?
A: Yes. With the valve turned to its fully open position, the back-seat design permits top O-ring replacement without taking the main pipeline out of service.
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